The author of the blockbuster novel "The Da Vinci Code" faces an English High Court challenge Monday from two men who claim he stole their ideas. Michael Baigent and Richard Leigh are suing their own publishers, Random House, claiming Dan Brown's book draws heavily on their 1982 bestseller "Holy Blood, Holy Grail".
Brown's 2003 book has sold more than 30 million copies worldwide and earned the American 45 million pounds (66 million euros, 78.5 million dollars) in one year, instantly making the writer one of the world's richest.
Baigent's and Leigh's book tackles theories that Jesus and Mary Magdalene married, had a child, and the blood line continues to the present day -- with the Catholic Church aware of the discovery and trying to suppress it.
A third author, Henry Lincoln, is not part of the lawsuit.
Brown's book, which combines thriller, detective and conspiracy theory genres, explores similar themes about the Vatican covering up the true story of Jesus.
The novel has been translated into 44 languages and drawn criticism from the Roman Catholic Church and historians.
If Baigent and Leigh are successful and obtain injunctions preventing the use of their material it could threaten the British release of the film adaptation of "The Da Vinci Code".
The big screen version, costing 100 million dollars and starring American two-time Oscar winner Tom Hanks, British veteran actor Sir Ian McKellen and French favourites Audrey Tatou and Jean Reno, is scheduled to open in Britain on May 19.
The case is expected to last up to two weeks, barring a settlement. It is also likely to clarify the extent to which an author can use other people's research under existing copyright laws.
Brown acknowledges the theories of "Holy Blood, Holy Grail" in his novel. The villain is called Sir Leigh Teabing, which bears a remarkable resemblance to Baigent and Leigh's surnames.
